Tow boat



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A. MODOUGALL.

. TOW BOAT.

No. 893,997. Patented Dec. 4, 1888.

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TOW BOAT.

Patented Dec. 4, 1888.

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June 20, 1882, for a tow-boat, I have described UNITED STATES PATENTOFFICE.

ALEXANDER MCDOI GALL, OF DULUTH, MINNESOTA TOW- BOAT.

SPECIFICATION forming part of Letters Patent No. 393,997, dated December4, 1888.

Application filed April 28, 1888. Serial No. 272,186. (No model.)

To all whom it may concern.-

Be it known that I, ALEXANDER MCDOU- GALL, a citizen of the lInitedStates, residing at Duluth, in the county of St. Louis and State ofMinnesota,have invented certain new and useful Improvements in'low-l-ioats; and I do hereby declare the following to be a full, clear,and exact description of the invention, which will enable others skilledin the art to which it appertains to make and use the same.

In Letters Patent No. 241,813, granted to me May 2.4, 1881, for atow-boat, and in other 1 Letters Patent, No. 259,880, granted to mecertain forms of hull and of the construction and arrangement of theframe and of turrets supporting working-decks as adapted to saidtow-boats, for the purpose designed.

In building a tow-boat of the character described, I have become awareof certain im provements over the inventions described and illustratedin said Letters Patent, which will better adapt the boat for thecarriage of oil, ores, coal, &c., which improvements I will proceed todescribe and afterward claim as new.

For the better iuulerstanding of these improvements reference should behad to the drawings, in which Figure 1 is-a side elevation of the hull,the center being broken out; Fig. 2, a vertical central cross-section ofthe hull. Fig. 3, a vertical cross-section at the bow on lines .1: :t:of Fig. I; Fig. at, a similar cross-section at the stern on lines y y ofFig. 1; Fig. 5, a vertical longitudinal section of the bow and forwardWorking-deck; Fig. 6, a similar section of the stern and afterworkingaleck Fig. '7, a detail of construction. of the upper deck, andFig. 8 details of construction of hatch and coinbings.

Similar letters denote COII'QSPOllCllDg' parts in each figure.

The hull A, pointed at both ends, designed to be built, preferably, ofsteel plates secured to steel ribs, each of which is continuousthroughout, is for the greater part of its length nearly fiat upon thebottom, with rounded corners, vertical sides, and a top, in the shape ofa flattened arch, springing from the point of loadline, as shown in thedrawings, in this respect differing from the shape of the towboatsdescribed and illustrated in my said 3 Letters Patent, and assuming morenearly a rectangular form with rounded corners. This form gives agreater carrying capacity with i the least d ralt, a matter of greatconsequence in shallow waters, while the rounded corners I give enoughof the arch shape to insure the requisite strength, with a frame andplates as light as possible. The bow, substantially semicircular at thecross-section .r .r for the upper half oi the hull, in the lower half ishollowed out, in this last respect beingoi a ell-known form. Theadvantage over this form of bow to prevent burying in waves and to allowthe bow to rise and ride easily over such waves. In like manner thestern at the crosssection 1 1 is oi a similar shape, the purpose beingto prevent the stern from sinking too deeply in rough seas. In both howand stern this form ditii'ers from that described and illustrated in myformer 1'iatents, where the crosssections in corresponding places havenearly the form of circles, with all lines rounded out and withouthollow lines. l'pon this hull A there is a skag, B, of such a size asenables me. to use a rudder, ot' the usual form in seagoing vessels, andcomparatively high and narrow instead of the low and wide one of theformer patents, by means of which, owing to the hollow run of the boat,I am enabled to use a rudder that is less liable to be destroyed orinjured in bad weather than the kind shown in said former patents.

In a boat such as I am now describing I prefer to have the width anddepth greater in proportion to the length than pointed out in saidpatent, No. 250,889, viz., about twenty live feet in width for a lengthof two hundred feet and a depth of about twenty feet; and I am enabledto make the hull suiticiently Strong for the carriage of ores and otherheavy material, while dispensing with the cross-beams E of saidlast-named patent, by substituting instead heavy main-deck beams D andbulkheads E, running the whole length or nearly the whole length of theboat, so as to divide the hull into several compartments, (three beingshown in the drawings) said bulk-heads i being firmly secured at the topto the maindeck beams and at the bottom to the floorbeams D, and havingstanchions E between said niaiircleck and the upper deck, in line i withthe bulk-heads E. The purpose of these bulk-heads is not to formwater-tight compartments, to keep the boat afloat if stove in at somepart, but to strengthen the hull and keep certain cargoes from shiftingposition. These bulk-heads are provided with sliding doors E atintervals conveniently corresponding with the hatchways, adapted to beraised by a tackle operated by the windlass or capstan.

Upon the main-deck F are numerous hatchways, G, arranged, preferably,along a central line, each hatch being composed, preferably, of a singleplate of metal of the proper size. To make good the strength of thisdeck, weakened by numerous hatchways, a strengthening-plate, a, may berun nearly the whole length of the boat on the under side of the beamsand directly below the hatch-combings l), which may be narrow platesrunning the length of each hatchway or running throughout the length ofthe entire series. The hatches G preferably hold their places by gravityalone, and are pulled in one direction to open the hatch and in theother to close the hatchways by ropes leading to the windlass orcapstan. The hatchways H and H on the upper deck, F, corresponding inposition to those in the main-deck, require more specific mention, as,with regard to them, there is need of excluding water when the hatchesare closed. Over the ribs which support this deck are lining-plates c oneach side of the hatchways and running the whole length of the boat.Upon this upper deck, F, are hatchcom'bings (1, running on each side ofthe hatchways the whole length of the series, each combing beingpreferably a narrow plate.

The hatches are maintained in position when the hatchways are closed bynumerous screw-bolts e, which pass down through the deck-plates and thelining-plates c. A rubber or other suitable elastic lining, f, isattached to I the under side of the hatch near its edges, 1 and thecompression of this lining by the screw-bolts e renders all the jointsabout the l hatches water-tight. Four other screw-bolts, gone at eachcorner of the hatchpass down 1 l through the same and rest at theirlower ends upon the deck-plates at the edges of the hatclr ways. Bysetting upon these screw-bolts af ter the screw-bolts e are removed thehatch is raised, so that it rides upon the ends of such screw-bolts g,and the hatch may be moved back or forth to cover or uncover thehatchway without injury to the rubber lining. These movements of thehatches in either direction are conveniently made by the use of thewindlass and capstan.

The bulk-heads, with sliding doors, the par ticular hatches andhatchways, and the 1 strengthening of the deck-beams, as just described,are neither described nor illustrated in either of my bef0re-n1entionedpatents. In my former patent, No. 259,889, I described and illustratedworking-decks at each end of the boat mounted upon turrets. To avoid thedanger of the waves striking such turrets climbing over them, I proposeto mount my working-decks K K on numerous pipes, h, properly secured tothe deck proper and to the under side of the working-deck, and to placein the forward working-deck and in the after part of it a smallcylinder, j, to afford a passage to the forecastle L, and anothercylinder, j, to carry the shaft to operate the Windlass. These decks Kand K are accessible from the main-deck by heavy metal ladders M M,arranged fore and aft, and firmly secured at each end, thereby bracingand supporting said decks very firmly. In the after working-deck K thereare small cylinders in line fore and aft-one, k, to give access to thecabin, another, 7;, for the capstan-shaft, and a third, 7;", for thechains for the steeringgear. In the loading of this tow-boat thelongitudinal bulk-heads prevent the shifting of the cargo in stormyweather, and in the unloading, the doors to the bulk-heads being raised,the entire cargo can be pumped out of the central compartment. Inloading ore, the doors being raised, the cargo can be con venicntlydistributed by hand into the side compartments, and, as such cargo isvery heavy and takes but little space, the dropping of the doors uponthe loaded cargo will effectively prevent the shifting of it in badweather.

Having thus described my improvements, what I claim as new thereinis- 1. The hull for a tow-boat with a central body nearly square incross-section, with vertical sides and rounded corners, and with sharpends, semi-cylindrical in the lines of the upper section, and withhollowed-out lines in the lower section thereof, substantially as setforth.

2. In combination with the hull of a towboat, hatchways arranged inseries, sliding hatches composed of a single plate of metal, andprovidedwith water-tight packing, screwbolts to fasten said hatches uponthe hatchways, and other screw-bolts to raise said hatches, so that thesame may be moved back and forth without injury to the packing.

In testimony whereof I affix my signature in presence of two witnesses.

\Vitnesses:

E. B. BRAOE, E. H. BERRY.

